Preliminary observations on the effects of stimulation of cardiac nerves in man

Abstract

The dorsal mediastinal cardiac nerves were stimulated in 20 patients undergoing coronary artery bypass surgery. In no instance was an untoward effect produced in any of the patients. Stimulation of a cardiac nerve increased heart rate in 8 patietns and slowed heart rate in 8 patients. In 12 patients stimulation of a cardiac nerve increased mean aortic pressure while in 8 patients it was decreased, even though the patients were supported by a total body perfusion pump. In 11 patients stimulation of a cardiac nerve resulted in a decrease in the coronary artery bypass graft flow, even though aortic pressure was unchanged or increased. Individual cardiac nerves in the dorsal mediastinum of man may be capable of modifying heart rate, total peripheral vascular resistance, or coronary artery resistance. Stimulation of human dorsal mediastinal cardiac nerves can be done without untoward effects and such stimulations may be a means to investigate the complexity of neural regulation of the human heart.